Expandable and collapsible table with nesting leaves

ABSTRACT

There is disclosed an expandable and collapsible table. In an embodiment, the expandable and collapsible table comprises a table frame including a center section having opposite outer edges, and a plurality of lateral supports hinged to the opposite outer edges of the center section of the table frame and at one or more center points along the length of each lateral support. The plurality of lateral supports are configured to allow the center section of the table frame to be expanded and collapsed in unison in substantially the same horizontal plane, to allow the table frame to be easily manipulated. The table legs can be mounted on locking wheels to allow the table to be easily manipulated for expansion and collapse. A plurality of leaves can be nested into one or more stacks to form a table top, or to be stored in a storage space underneath the table top.

FIELD OF THE INVENTION

The present disclosure relates generally to expandable and collapsibletables.

BACKGROUND OF THE INVENTION

Various expandable and collapsible table designs have been proposed inthe past in order to provide an expandable table to accommodateadditional seats around the table when required, and to reduce the tablefootprint by collapsing the table when the additional seats are notrequired.

For example, a conventional expandable dining table may be expanded bypulling apart two halves of the table top supported on slides, andinserting one or more leaves therebetween to bridge the gap between thetwo halves of the expanded table surface to accommodate additionalpeople at the dining table. However, even when not expanded, aconventional dining table still takes up a significant amount of space,and normally requires a formal dining room or a designated dining areato provide sufficient room for the table. As well, the extension leavesmust usually be stored separately when not in use, and brought out ofstorage when needed for the expanded table.

Various other types of expandable and collapsible table designs havebeen proposed. As an example, DE 9216847 (Thomas) discloses anexpandable and collapsible table with a scissor lattice-like supportstructure which can be expanded and collapsed to provide support for atable top. However, the scissor lattice-like support structure does notprovide any edge support. Instead, Thomas relies on a one-piece tabletop to have sufficient structural strength to provide the necessarystructural support, including edge support in the open spaces betweenpoints of contact between the scissor lattice-like supports and thetable top. Furthermore, the scissor lattice-like support structure mustbe braced in some way to the table top in order to keep the table in anexpanded position.

Other expandable table designs may be expandable in more than onedimension. For example, U.S. Pat. No. 745,116 (Peterson) discloses atable that extends in two directions using a set of extendable slides. Aplurality of leaves may be positioned over the extendable slides to forma larger table surface area. However, Peterson does not deal with howand where to store the additional leaves, and the operation required toexpand the table in two directions, while at the same lima making all ofthe leaves fit properly, may be cumbersome.

As yet another example, WO 2004/044043 (Young) discloses a table withquarter sections that are extendable along telescoping elongate membersconnected at a junction, and which accommodates leaves to cover anyspace created between the table sections when extended. However, Youngalso does not deal with the issue of how to store the additional leaves,and the operation to extend the table to insert the leaves may not beeasy to perform.

U.S. application Ser. No. 11/357,435, published as US 2007/0204772(Evans) discloses a storage table system and method which allows hingedsections of the table top to be folded onto other portions of the table,and be rotated over a supporting frame. While Evans allows sections ofthe table top to be folded onto itself, the number of steps required tofold or unfold the table top and expand or collapse the support can beunwieldy if the steps are not followed properly.

Therefore, what is needed is an improved expandable/collapsible tablethat overcomes at least some of the limitations identified above.

SUMMARY OF THE INVENTION

The present disclosure relates generally to an expandable andcollapsible table configured to provide ease of use when transformedbetween one or more expanded states and a completely collapsed state. Byusing a novel, hinged expansion mechanism, the table maintainsstructural stability as it transitions between all different states. Byproviding table legs that are supported on wheels, one person can easilymanipulate the table between one or more expanded states and itscollapsed state.

The expandable and collapsible table of the present invention isparticularly well suited to small living areas such as apartments,condominiums and smaller townhomes, where living space is at a premiumand furniture with a small footprint is highly desirable.

Thus, in an aspect, there is provided an expandable and collapsibletable, comprising: a table frame including a center section havingopposite outer edges; and a plurality of lateral supports hinged to theopposite outer edges of the center section of the table frame and at oneor more center points along the length of each lateral support; wherebythe plurality of lateral supports are configured to allow the centersection of the table frame to be expanded and collapsed.

In an embodiment, each lateral support is hinged to the opposite outeredges, and at one or more points along a length of each lateral support,whereby the plurality of lateral supports are expandable and collapsiblein unison in substantially the same horizontal plane.

In another embodiment, the plurality of lateral supports are collapsibleinto a substantially V-shape such that at least one hinged lateralsupport is collapsible inside another hinged lateral support within thesame horizontal plane.

In another embodiment, the table further comprises telescoping ends oneither side of the center section of the table frame, each telescopingend including at least one hinged lateral support forming an edge of thetable frame and configured to expand the table longitudinally.

In another embodiment, the table further comprises legs supporting theframe, each leg mounted on a wheel to allow the table frame to beexpanded and collapsed.

In another embodiment, the legs are mounted to the telescoping ends suchthat the legs remain at outer corners of the table frame in anyexpansion state, thereby maintaining structural stability of the tableframe between different expansion states.

In another embodiment, the wheel includes a locking mechanism to preventthe table from moving.

In another aspect, there is provided a table frame for an expandable andcollapsible table, comprising: a center section having opposite outeredges; and a plurality of lateral supports hinged to the opposite outeredges of the center section and at one or more center points along thelength of each lateral support, whereby the plurality of lateralsupports are expandable and collapsible in unison in substantially thesame horizontal plane to allow the center section of the table frame tobe expanded and collapsed laterally.

Other features and advantages of the present invention will becomeapparent from the following detailed description and accompanyingdrawings. It should be understood, however, that the detaileddescription and specific examples are given by way of illustration andnot limitation. Many modifications and changes within the scope of thepresent invention may be made without departing from the spirit thereof,and the invention includes all such modifications.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an illustrative perspective view of the table in acompletely collapsed state.

FIG. 2 shows an illustrative perspective view of the table of FIG. 1 ina completed expanded state.

FIGS. 3A to 3D show illustrative top views of a table frame in acompletely collapsed state, a completely expanded state, and someintermediate states.

FIG. 4 shows an illustrative detailed perspective view of the tableframe within hinged lateral supports shown in a partially expandedstate.

FIG. 5 shows an illustrative perspective view of the table frame in afully expanded state.

FIGS. 6A AND 6B show a detailed view of a plurality of loaves nestedinto one or more stacks.

FIGS. 7A and 7B show illustrative embodiments of Sifting mechanisms tolift a stack of nested leaves off the top of the table frame.

FIG. 8 shows an illustrative perspective view of a locking mechanism inaccordance with an embodiment for locking edges of leaves to the tableframe.

FIGS. 9A-9D show illustrative views of leaves being positioned invarious alternative configurations.

In the drawings, embodiments of the invention are illustrated by way ofexample. It is to be expressly understood that the description anddrawings are only for the purpose of illustration and as an aid tounderstanding, and are not intended as a definition of the limits of theinvention.

DETAILED DESCRIPTION

As noted above, the present disclosure relates generally to anexpandable and collapsible table. Advantageously, by using a novelexpansion mechanism comprising a plurality of hinged lateral supports,the table maintains structural stability as it transitions between alldifferent states.

In an embodiment, by providing table legs that are supported on wheels,one person can easily manipulate the table between one or more expandedstates and its collapsed state.

In an illustrative embodiment, the table can be expanded to increase itstable top surface area to approximately six times the table surface areawhen the table is in a completely collapsed state. This is achieved bydesigning the table to be expandable and collapsible laterally andlongitudinally. In a longitudinal direction, the table may be expandedonly partially, if the full length of the expanded table is notrequired. In one or more partially expanded states, or in a fullyexpanded state, the table frame supports a plurality of leaves which cancover the entire surface of the table frame.

In other embodiments, the table can be expanded greater than six timesthe original surface area by providing hinged lateral supports withlonger arms to expand the table frame further laterally, and one or moretelescoping sections on each end which can expand the table framefurther longitudinally.

In an embodiment, the plurality of leaves are nestable, wherein theleaves are sized to be incrementally larger than (or incrementallysmaller than) the next leaf such that they can be stacked together toform one or more stacks of nested leaves. If all of the leaves areincrementally sized to be nestable in a single stack, the nested leavescan be stacked to form a single table top surface.

An illustrative example of a table will now be described in more detailwith reference to the figures.

FIG. 1 shows an illustrative view of the table 100 in a completelycollapsed state. As shown, the table 100 includes a leg 110 at eachcorner, and each leg 110 is preferably mounted on a wheel 120. Thewheels 120 may be, for example, locking caster wheels that can swivel inany direction. As will be described in more detail below, the wheels 120allow the table legs 110 to be easily manoeuvred relative to each otherwhile expanding or collapsing the table 100. Once the table 100 is in adesired state of expansion, the wheels 120 can be locked to prevent thetable 100 from moving.

Still referring to FIG. 1, the table top 150 may be comprised of a stackof nested leaves, the top leaf shown as 160A, which cover the top of thetable 100 in its completely collapsed state. As will be explained inmore detail below, the nested leaves can be individually laid out tocover the surface of the table 100 in one or more expanded states.

Now referring to FIG. 2, shown is an illustrative view of the table 100of FIG. 1 in a fully expanded state, with a plurality of leaves160A-160C, 162A-162C, 164A-164C fully laid out to cover the expandedsurface of table 100. In an embodiment, each of the plurality of leaves160A-160C, are configured to be incrementally larger (or smaller) thanthe next adjacent leaf, such that the leaves 160A-160C can be nestedtogether in one stack. Similarly, leaves 162A-162C are configured to benestable into a stack, and leaves 162A-162C are also configured to benestable into a stack. If appropriately steeds the stacks formed fromleaves 162A-162C, and from leaves 164A-164C, may also be stackedtogether with the stack formed from leaves 162A-162C.

Now referring to FIGS. 3A-3D, shown are top views of a table frame 200in various stages of expansion. As shown, the table frame 200 isexpandable in a first direction by a plurality of hinged lateralsupports 210, 212 as shown in FIG. 3A, each comprising at least twosections 210 a, 210 b, 212 a, 212 b.

As shown in FIG. 3A, hinged lateral supports 210, 212 are configuredsuch that they form a substantially V-shape when collapsed, and areexpandable and collapsible in unison in substantially the samehorizontal plane. More particularly, in an embodiment, hinged lateralsupport 212 is collapsible inside hinged lateral support 210 within thesame horizontal plane when the table frame 200 is fully collapsed.

In an embodiment, the hinged lateral supports 210, 212 are hinged at aplurality of locations as shown in FIG. 3B, including one or more hinges230 at or near a center point of each lateral support 210, 212, and ahinge 230 near each end of the hinged lateral supports 210, 212 nearopposite outer edges 240 of a center section 250 of the table frame 200.Each hinged lateral support 210, 212 is thus configured to extend fullyinfo a substantially straight line, as shown in FIG. 3B, or to collapsesubstantially into a horizontally folded shape as shown in FIG. 3A, whenthe table frame 200 is collapsed.

With reference to FIGS. 3B-3D, the table frame 200 further includes twotelescoping ends 260 slideably fitted within center section 250, forexample by a nylon sleeve 255 (see FIG. 7B) provided between the centersection 250 and the telescoping ends 260. As shown, both telescopingends 260 are shown fully extended in a longitudinal direction as shownin FIG. 3B, fully collapsed as shown in FIG. 3C, or partially extendedon one side as shown in FIG. 3D. As will be appreciated, the table frame200 provides a number of different configurations in which the table maybe used in different states of expansion suitable for a particular use.

In certain configurations, such as shown in FIG. 3C, alternate leaves166A-166C, 168A-168C may be used to cover end sections of the table 100when the telescoping ends 260 are fully retracted, as otherwise a partof the table frame 200 would remain uncovered near their ends.Alternatively, as shown in FIG. 3D, if only one telescoping end 260 isextended, alternative leaves 166A-166C can be placed on the retractedside, and leaves 164A-164C can be used to cover the extended side.

In an embodiment, a telescoping end 260 may include a plurality oftelescoping sections, such that each telescoping end 260 can be extendedeven further than shown in FIGS. 3A-3D. However, the number oftelescoping sections should be limited in order to maintain structuralintegrity of the table frame when fully extended.

Still referring to FIGS. 3A-3D, the table frame 200 may be made from anysuitable structural material including but not limited to steel,aluminum, wood, plastics, and carbon fiber. Specific parts of the frame200 may also be made from wood or wood veneer for decorative purposes.

Now referring to FIG. 4, shown is an illustrative detailed perspectiveview of the table frame 200 within hinged lateral supports 210, 212shown in a partially expanded state. This detailed view shows how thehinged lateral supports 210, 212 maintain a gap between them throughouttheir range of motion, until they are fully extended. The hinges 230 canbe configured to provide minimal rotational resistance, such that thehinged lateral supports 210, 212 allow a user to easily extend the tableframe 200 laterally by pulling the two sides of the table frame 200apart from one end. Having all four legs 110 mounted on swivellingcaster wheels 120 also facilitates easy operation in expanding andcollapsing the table frame 200 laterally and longitudinally.Furthermore, legs 110 are mounted to each corner of the telescoping ends260 and are configured such that they will maintain their position atouter corners of the table frame 200 regardless of the expansion stateof the table 100. Thus, the structural stability of the table 100 isalways maintained in any state of expansion or collapse of the table100.

Still referring to FIG. 4, hinged lateral supports 210, 212 include anumber of vertically extending tabs 270 or slots 280 which areappropriately positioned to receive the edges of the leaves 160A-160C,162A-162C, 164A-164C when placed on top of the table frame 200. Eachvertically extending tab 270 can provide support for one edge of a leaf,whereas each vertically extending slot 280 can accommodate two edges ofadjacently positioned leaves. The height of these vertically extendingtabs 270 or slots 280 is substantially the same, such that leaves160A-160C, 162A-162C, 164A-164C placed on top of the verticallyextending tabs 270 or slots 280 will form a substantially flat table topsurface. A lifting mechanism 300 is shown mounted to one side of thecenter section 250 of the table frame. This feature will be explained inmore detail further below.

Now referring to FIG. 5, shown is a perspective view of the table frame200 in a fully expanded state, including telescoping ends 260 which havebeen fully extended longitudinally. With each of the hinged lateralsupports 210, 212 fully extended laterally in a substantially straightline, and the telescoping ends 260 fully extended longitudinally, thevertically extending tabs 270 or slots 280 are aligned both laterallyand longitudinally to accept the leaves 160A-160C, 162A-162C, 164A-164Cin position, substantially as shown earlier in FIG. 2 and FIG. 3B.

Now referring to FIGS. 6A and 6B, shown are top and side views,respectively, of leaves 160A-160C, 162A-162C, 164A-164C nested into aplurality of stacks. As shown, in each stack, the leaves 160A-160C,162A-162C, 164A-164C are sized to be incrementally larger (or smaller)than other leaves in the stack to nest in the manner as illustrated. Inan embodiment, the leaves 160A-160C, 162A-162C, 164A-164C are preferablymade of a light material which still provides structural strength. Forexample, the leaves 160A-160C, 162A-162C, 164A-164C may be made of analuminum alloy which allows the leaves 160A-160C, 162A-162C, 164A-164Cto be easily handled and lifted even when nested together in one stack.However, this is not meant to be limiting, and the leaves 160A-160C,162A-162C, 164A-164C may be made of any suitable rigid materialincluding, but not limited to, steel, aluminum, wood, plastics andcarbon fiber.

Now referring to FIGS. 7A and 7B, shown are illustrative embodiments oflifting mechanisms 300A, 300B which are configured to lift leaves160A-160C from the top of table 100. For example, as shown in FIG. 7A,lifting mechanism 300A is mounted to one side of a center section 200 ofthe table frame 200. Lifting mechanism 300A may include perpendicularsupports 310 at a free end to balance a stack of nested leaves 160A-160Cbeing lifted off the table frame 200. On the other end, liftingmechanism 300A may be mounted via a hinge 320 configured to lift thelifting mechanism 300A upwardly when handle 330 is operated and pulleddownwardly. It will be understood that this lining mechanism 300A isillustrative, and that other configurations for lifting the leaves160A-160C off the table are possible. As another example, as shown inFIG. 7B, an alternative lifting mechanism 300B is shown in which, ahandle 330 is attached to a cam 340 which raises lifting mechanism 300Balong a trajectory defined by slots 350, 360, which raises liftingmechanism 300B such that both sides of leaves 160A-160C are lifted atthe same time. This allows the near side of leaves 160A-160C to avoidgetting caught on the edge of the table frame 200. Also shown in FIG. 7Bare cross-sectional views of center section 250, telescoping end 260,and a nylon sleeve 255 provided therebetween.

Now referring to FIG. 8, shown is an illustrative perspective view of alocking mechanism 800 in accordance with an illustrative embodiment forlocking edges of up to four adjacent leaves 160A-160C, 162A-162C,164A-164C to the table frame 200. As shown, locking mechanism 800includes a pair of brackets 810 a, 810 b and a horizontally oriented “H”frame 820 mounted to a top surface of table from 200 (e.g. to a topsurface of hinged lateral supports 210 replacing a pair of verticallyextending slots 280 shown in FIG. 5, for example). Each bracket 810 a,810 b may include vertically extending tabs with slots 812 a, 812 bconfigured to slidably receive a cylindrical pin 830.

Still referring to FIG. 8, shown are cooperating edges leaves 160A and164A. Each of the leaves 160C and 164A include semi-circular notches 832for mating to a cylindrical pin 830. In this illustrative embodiment,leaf 164A further includes a rectangular notch 836 which accommodates abridge portion 822 of the “H” frame 820 and leaves a protrusion 834sitting atop of the bridge portion 822 of the “H” frame 820. Inoperation, the sliding cylindrical pin 830 acts to lock the two leaves160A, 164A in position, and may further receive to more adjacent leaves160B, 164B into the same locking mechanism.

Now referring to FIGS. 9A-9D, shown are illustrative perspective viewsof the leaves 160A-160C, 162A-162C, 164A-164C being positioned invarious locations atop the table frame 200. As each leaf 160A-160C,162A-162C, 164A-164C is independently positionable, the leaves160A-160C, 162A-162C, 164A-164C can be positioned to cover the table topin various, alternative configurations.

Thus, in an aspect, there is provided an expandable and collapsibletable, comprising: a table frame including a center section havingopposite outer edges; and a plurality of lateral supports hinged to theopposite outer edges of the center section of the table frame and at oneor more center points along the length of each lateral support; wherebythe plurality of lateral supports are configured to allow the centersection of the table frame to be expanded and collapsed.

In an embodiment, each lateral support is hinged to the opposite outeredges, and at one or more points along a length of each lateral support,whereby the plurality of lateral supports are expandable and collapsiblein unison in substantially the same horizontal plane.

In another embodiment, the plurality of lateral supports are collapsibleinto a substantially V-shape such that at least one hinged lateralsupport is collapsible inside another hinged lateral support within thesame horizontal plane.

In another embodiment, the table further comprises telescoping ends oneither side of the center section of the table frame, each telescopingend including at least one hinged lateral support forming an edge of thetable frame and configured to expand the table longitudinally.

In another embodiment, the table further comprises legs supporting theframe, each leg mounted on a wheel to allow the table frame to beexpanded and collapsed.

In another embodiment, the legs are mounted to the telescoping ends suchthat the legs remain at outer comers of the table frame in any expansionstate, thereby maintaining structural stability of the table framebetween different expansion states.

In another embodiment the wheel includes a locking mechanism to preventthe table from moving.

In another embodiment, the table frame further comprises a top surfaceincluding tabs or slots adapted to receive a plurality of table leaves.

In another embodiment, the tabs or slots are further adapted to receiveedges of a plurality of adjacent leaves.

In another embodiment, the tabs or slots extent above the table frame atsubstantially the same height such that the plurality of adjacent leavescovering the table frame are substantially flat.

In another embodiment, the tabs or slots include movable locking pins totemporarily lock down one of more leaves thereon.

In another embodiment the table leaves are shaped and sized to beincrementally larger or incrementally smaller than one another such thatthe table leaves are nestable within one or more stacks.

In another embodiment, at least some of the table leaves are nestablewithin one stack to form a table top when the table is in a completelycollapsed state.

In another embodiment, the table frame further comprises a liftingmechanism mounted to one side of the center section of the table frame,the lifting mechanism configured to lift a stack of nested leaves offthe top surface of the table.

In another embodiment, the table frame further comprises a storage spaceunderneath the table top to store one or more additional stacks of tableleaves.

In another embodiment, alternative table leaves are provided for usewhen the table is in different expansion states.

In another embodiment, the table leaves are one of steel, aluminum,wood, plastic and carbon fiber.

In another embodiment, the table frame is one of steel, aluminum, wood,plastic and carbon fiber.

In another embodiment, the table legs are one or more of steel,aluminum, wood, plastic, carbon fiber.

In another aspect, there is provided a table frame for an expandable andcollapsible table, comprising: a center section having opposite outeredges; and a plurality of lateral supports hinged to the opposite outeredges of the center section and at one or more center points along thelength of each lateral support, whereby the plurality of lateralsupports are expandable and collapsible in unison in substantially thesame horizontal plane to allow the center section of the table frame tobe expanded and collapsed laterally.

While various embodiments and illustrative examples have been describedabove, it will be appreciated that these embodiments and illustrativeexamples are not limiting, and the scope of the invention is defined bythe following claims.

1. An expandable and collapsible table, comprising: a table frame including a center section having opposite outer edges; and a plurality of lateral supports hinged to the opposite outer edges of the center section of the table frame and at one or more center points along the length of each lateral support; whereby the plurality of lateral supports are configured to allow the center section of the table frame to be expanded and collapsed.
 2. The expandable and collapsible table of claim 1, wherein each lateral support is hinged to the opposite outer edges, and at one or more points along a length of each lateral support, whereby the plurality of lateral supports are expandable and collapsible in unison in substantially the same horizontal plane.
 3. The expandable and collapsible table of claim 2, wherein the plurality of lateral supports are collapsible into a substantially V-shape such that at least one hinged lateral support is collapsible inside another hinged lateral support within the same horizontal plane.
 4. The expandable and collapsible table of claim 3, wherein the table further comprises telescoping ends on either side of the center section of the table frame, each telescoping end including at least one hinged lateral support forming an edge of the table frame and configured to expand the table longitudinally.
 5. The expandable and collapsible table of claim 1, wherein the table further comprises legs supporting the frame, each leg mounted on a wheel to allow the table frame to be expanded and collapsed.
 6. The expandable and collapsible table of claim 5, wherein the legs are mounted to the telescoping ends such that the legs remain at outer corners of the table frame in any expansion state, thereby maintaining structural stability of the table frame between different expansion states.
 7. The expandable and collapsible table of claim 6, wherein the wheel includes a locking mechanism to prevent the table from moving.
 8. The expandable and collapsible table of claim 1, wherein the table frame further comprises a top surface including tabs or slots adapted to receive a plurality of table leaves.
 9. The expandable and collapsible table of claim 8, wherein the labs or slots are further adapted to receive edges of a plurality of adjacent leaves.
 10. The expandable and collapsible table of claim 9, wherein the tabs or slots extent above the table frame at substantially the same height such that the plurality of adjacent leaves covering the table frame are substantially flat.
 11. The expandable and collapsible table of claim 9, wherein the tabs or slots include movable locking pins to temporarily lock down one or more leaves thereon.
 12. The expandable and collapsible table of claim 8, wherein the table leaves are shaped and sized to be incrementally larger or incrementally smaller than one another such that the table leaves are nestable within one or more stacks.
 13. The expandable and collapsible table of claim 12, wherein at least some of the table leaves are nestable within one stack to form a table top when the table is in a completely collapsed state.
 14. The expandable and collapsible table of claim 8, wherein the table frame further comprises a lifting mechanism mounted to one side of the center section of the table frame, the lifting mechanism configured to lift a stack of nested leaves off the top surface of the table.
 15. The expandable and collapsible table of claim 14, wherein the table frame further comprises a storage space underneath the table top to store one or more additional stacks of table leaves.
 16. The expandable and collapsible table of claim 8, wherein alternative table leaves are provided for use when the table is in different expansion states.
 17. The expandable and collapsible table of claim 16, wherein the table leaves are one of steel, aluminum, wood, plastic and carbon fiber.
 18. The expandable and collapsible table of claim 1, wherein the table frame is one of steel, aluminum, wood, plastic and carbon fiber.
 19. The expandable and collapsible table of claim 5, wherein the table legs are one or more of steel, aluminum, wood, plastic and carbon fiber.
 20. A table frame for an expandable and collapsible table, comprising: a center section having opposite outer edges; and a plurality of lateral supports hinged to the opposite outer edges of the center section and at one or more center points along the length of each lateral support, whereby the plurality of lateral supports are expandable and collapsible in unison in substantially the same horizontal plane to allow the center section of the table frame to be expanded and collapsed laterally. 